package demo1;

public class StringBuilderDemo1 {
    public static void main(String[] args) {
        StringBuilder s1 = new StringBuilder("111");
        s1.append("Hello").append("123").append("456");
        s1.append("!");
       // s1.reverse();

        String s2 = s1.toString();
        System.out.println(s2);
    }
}
